TWI836173B - Apparatus for and method of control of a charged particle beam - Google Patents

Abstract

An apparatus comprising a set of pixels configured to shape a beamlet approaching the set of pixels and a set of pixel control members respectively associated with each of the set of pixels, each pixel control member being arranged and configured to apply a signal to the associated pixel for shaping the beamlet.

Description

Devices and methods for controlling charged particle beams

Embodiments described herein relate to a charged particle device having one or more charged particle beams, such as an electron microscopy apparatus utilizing one or more electron beams.

Integrated circuits are made by creating patterns on a wafer (also called a substrate). The wafer is supported on a wafer stage in the equipment used to create the pattern. Part of the process used to make integrated circuits involves viewing or "inspecting" portions of the wafer. This can be done with a charged particle system such as a scanning electron microscope, or SEM.

Traditional microscopes use visible light and one or more clear lenses or mirrors to make objects as small as about one micron visible. The resolving power of this microscope is limited by the wavelength of light used for illumination. Charged particle systems use charged particle beams instead of light and use electromagnetic or electrostatic lenses to focus the particles. It can measure position with an accuracy as small as one-tenth of a nanometer.

Typically, systems for focusing charged particles at a single point on a sample use two or more electromagnetic or electrostatic lenses. However, real lenses do not focus exactly to a single point. For example, the second lens can distort the wavefront of the charged particle beam. These deviations from a perfect lens are called aberrations of the lens. Aberrations cause the image formed by the lens to be blurred or distorted. Aberrations can be reduced, for example, using phase plates with multiple apertures, but this comes at the expense of reducing the beam current.

Embodiments of the present invention provide a multi-beam detection device, and more particularly, a single-beam or multi-beam detection system including an improved beam steering unit. In some embodiments, the detection system includes: a source of a beamlet of charged particles, a beam splitter for directing the beamlet, and a programmable charged particle mirror panel, the programmable A charged particle mirror panel is configured to receive the plurality of beamlets from the beam splitter and configured to correct aberrations of the beamlets. The mirror panel includes: a first group of pixels configured to shape a first beamlet close to the first group of pixels; and a first group of pixel control components respectively connected to the first group of pixels. Associated with each, each pixel control member is configured and configured to apply a signal to the associated pixel for shaping the first beamlet.

In some embodiments, a system for manipulating a charged particle beam is provided. The system includes: a source of a beamlet of charged particles, a beam splitter for guiding the beamlet, and a programmable charged particle mirror panel, the programmable charged particle mirror panel being configured to receive the guided beamlet from the beam splitter and configured to shape the beamlet.

In some embodiments, a method for shaping a beamlet of charged particles is provided. The method includes: directing a first beamlet of charged particles toward a charged particle mirror panel using a beam splitter; and shaping the first beamlet by providing a signal to a first set of pixels of the charged particle mirror panel to generate an electric field and reflecting the shaped beamlet from the charged particle mirror panel to the beam splitter.

In some embodiments, a non-transitory computer-readable medium is provided that stores instructions for executing, by a processor, a method for shaping a beamlet of charged particles. The method includes directing a first beamlet of charged particles toward a charged particle mirror panel using a beam splitter; and by providing a signal to a first group of charged particle mirror panels. The pixels generate an electric field to shape the first beamlet and the charged particle mirror panel reflects the shaped beamlet to the beam splitter.

1: Exemplary charged particle beam detection system

10:Main chamber

20:Loading/locking chamber

30: Equipment front-end module (EFEM)

30a: First loading port

30b: Second loading port

100: Electron Beam Tools

100A: Electron beam tools/devices

100B: Electron beam tools/devices

100C: Electron beam tools/devices

102: Yang pole

103:Cathode

105:Axis

109:Controller

122: gun bore diameter

125: beam limiting aperture

126: Focusing lens

132:Objective lens assembly

132a: Pole piece

132b: Control electrode

132c: Deflector

132d: Excitation coil

134: Mobile stage

135: Column aperture

136: Wafer holder

144:Detector

148: Quadrupole lens

150:wafer

158: Beam splitter

161:Primary beam

170: Beam point

202:Electron source

204: Gun bore

206: condenser lens

208: Crossover

211: Primary electron beam

212: Source conversion unit

214:Small beam

216:Small beam

218: Small beam

220: Primary projection optical system

222: Beam splitter

226: Deflection scanning unit

228:Objective lens

230: Wafer

236:Secondary electron beam

238:Secondary electron beam

240:Secondary electron beam

242:Secondary optical system

244: Electronic detection devices

246: Detection sub-area

248: Detection sub-area

250: Detection sub-area

252: Auxiliary optical axis

270: Detect light spot

272: Detect light spots

274: Detect light spots

300: Programmable charged particle mirror panel

301:pixel

302:Electron source/pixel

303:pixel

304: Pixels

305:pixel

306: First lens/pixel

307:pixel

322: Beam splitter

328:Second lens

340:Sample

350: Voltage control

351: Pixel control component/voltage control

352: Pixel control component/voltage control

353: Pixel control component/voltage control

354: Pixel control component/voltage control

355: Pixel control component/voltage control

356: Pixel control component/voltage control

357: Pixel control component/voltage control

361: small beam

361r: Small beam

370: Sample surface

390: Equipotential plane

400: Programmable pixelated mirror panel

401:Pixels

402:Pixels

403:pixel

404:Pixels

405:Pixels

411:pixel

412: pixels

413: pixels

414:pixel

415: pixels

421: pixels

422: pixels

423:pixel

424: pixels

425: pixels

450: Voltage control

451:Control components

452: Control components

453:Control components

454: Control components

455: Control components

461: Control components

462:Control components

463:Control components

464: Control components

465:Control components

471:Control components

472:Control components

473: Control components

474:Control components

475: Control components

491: Equipotential plane

492: Equipotential plane

493: Equipotential plane

500:Methods

510: Steps

520: Steps

530: Steps

The above and other aspects of the invention will become more apparent from the description of illustrative embodiments taken in conjunction with the accompanying drawings.

FIG1 is a schematic diagram illustrating an exemplary charged particle beam detection system according to an embodiment of the present invention.

FIG. 2A is a diagram illustrating an example charged particle beam apparatus that may be an electron beam tool consistent with an embodiment of the present invention, which may be a part of the exemplary electron beam detection system of FIG. 1 .

2B is a diagram illustrating a multi-beam charged particle beam apparatus that may be an example of an electron beam tool that may be part of the exemplary electron beam inspection system of FIG. 1 consistent with embodiments of the invention.

3A illustrates an exemplary electron beam tool that may be part of the charged particle beam detection system of FIG. 1 consistent with embodiments of the present invention.

FIG. 3B is a schematic diagram illustrating the operation of a programmable pixelated mirror panel and voltage control in accordance with an embodiment of the present invention.

FIG. 3C is another schematic diagram illustrating the operation of a programmable pixelated mirror panel and voltage control in accordance with an embodiment of the present invention for correcting different aberrations of different beamlets in a multi-beam system.

FIG. 4 is a flow chart illustrating an exemplary method for correcting aberrations of a beamlet in accordance with an embodiment of the present invention.

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, wherein the same reference numerals in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following description of the exemplary embodiments do not represent all implementations consistent with the present invention. Instead, they are merely examples of systems, devices, and methods that are consistent with the aspects of the present invention described in the attached patent claims. For the sake of clarity, the relative sizes of the components in the drawings may be exaggerated.

Electronic devices are made up of circuits formed on a block of silicon called a substrate. Many circuits can be formed together on the same block of silicon and are called an integrated circuit or IC. The size of these circuits has been reduced dramatically so that many of them can fit on a substrate. For example, an IC chip in a smartphone can be as small as a thumbnail and still include over 2 billion transistors, each less than 1/1000 the size of a human hair.

Manufacturing these tiny ICs is a complex, time-consuming, and expensive process that often involves hundreds of individual steps. An error in even one step has the potential to result in defects in the finished IC that render it useless. Therefore, one goal of the manufacturing process is to avoid such defects in order to maximize the number of functional ICs manufactured in the process, i.e., to improve the overall yield of the process.

One component of improving yield is monitoring the chip manufacturing process to ensure that it is producing a sufficient number of functional integrated circuits. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection can be done using a scanning electron microscope (SEM). The SEM can be used to actually image these extremely small structures, thereby obtaining an "image" of the structures. The image can be used to determine whether the structure was properly formed, and also determine whether the structure was formed in the proper location. If the structure is defective, the process can be adjusted so that the defect is less likely to recur.

An image of a wafer can be formed by scanning a primary beam of an SEM system across the wafer and collecting particles (e.g., secondary electrons) generated from the wafer surface at a detector. The imaging process can include focusing the primary beam to a point and deflecting (e.g., bending) the beam so that it passes over an area of the wafer in a line-by-line pattern (e.g., grating scanning). At a given time, the beam can be focused to a specific location on the wafer, and the output of the detector at that time can be associated with that specific location on the wafer. An image can be reconstructed based on the detector output at each time along the beam scan path.

Factors that affect the quality of imaging, such as the quality of images produced by a SEM, include image resolution. Image resolution can be determined by the ability of a beam to be focused to a point. Resolution becomes increasingly important as feature sizes on IC chips continue to decrease, such as to 5nm and 3nm node sizes. Resolution can be affected by various distortions or aberrations that may be introduced into the SEM system. Aberrations such as field curvature, astigmatism, and chromatic aberrations can be caused as the beam travels through the lens.

To account for aberrations, existing systems may use, for example, programmable phase plates containing apertures. Each of the apertures is connected to a voltage configured to supply voltage to the corresponding aperture to correct aberrations of the beam passing through the aperture. Although programmable phase plates reduce aberrations, they result in a loss of beam current when part of the beam does not fall on one of the apertures. Beam transmission losses can further limit the throughput of an SEM system.

To enhance the performance of SEM systems, it would be desirable to correct aberrations without reducing the beam current and without inhibiting the operational flexibility of the SEM system. For example, it would be desirable to maintain adjustability over a wide range of SEM system parameters such as primary beam energy, beam opening angle, and the energy of secondary electrons reaching the detector.

Embodiments of the present invention may solve problems such as those discussed above by reducing the effects of aberrations. Adjustable without considerable beam current loss and without compromising operating parameters Reduce aberrations when possible. For example, after the beam passes through a lens, the beam can be shaped to correct for any aberrations introduced by the lens. Shaping can be performed with mirror panels.

An exemplary mirror panel may include a set of pixels, wherein each pixel is associated with a voltage control. The voltage control provides a voltage to the corresponding pixel, thereby affecting the charged particles of the beam as they approach the pixel. By affecting the charged particles, the pixels of the mirror panel assist in shaping the beam or correcting aberrations introduced by the lens.

Without limiting the scope of the invention, the description and drawings of the embodiments may be exemplarily referred to as using electron beams. However, the examples are not intended to limit the invention to specific charged particles. For example, systems and methods for beamforming may be applied to ions and the like. Furthermore, the term "beam" may refer to a primary electron beam, a primary electron beamlet, a secondary electron beam or a secondary electron beamlet, among others.

Referring now to FIG. 1 , a schematic diagram illustrates an exemplary charged particle beam detection system 1 consistent with embodiments of the present invention. As shown in FIG. 1 , the charged particle beam detection system 1 includes a main chamber 10 , a load/lock chamber 20 , an electron beam tool 100 , and an equipment front-end module (EFEM) 30 . The electron beam tool 100 is located within the main chamber 10 . Although the description and drawings are directed to electron beams, it should be understood that the examples are not intended to limit the invention to specific charged particles.

The EFEM 30 includes a first loading port 30a and a second loading port 30b. The EFEM 30 may include additional loading ports. The first loading port 30a and the second loading port 30b may, for example, receive wafer front opening unit pods (FOUPs) containing wafers (e.g., semiconductor wafers or wafers made of other materials) or samples to be inspected (wafers and samples are collectively referred to as "wafers" hereinafter). One or more robot arms (not shown) in the EFEM 30 transport the wafers to the loading/locking chamber 20.

The load/lock chamber 20 may be connected to a load/lock vacuum pump system (not shown). shown), which removes gas molecules in the loading/locking chamber 20 to achieve a first pressure below atmospheric pressure. After the first pressure is reached, one or more robotic arms (not shown) transport the wafers from the load/lock chamber 20 to the main chamber 10 . The main chamber 10 is connected to a main chamber vacuum pump system (not shown in the figure), which removes gas molecules in the main chamber 10 to reach a second pressure lower than the first pressure. After reaching the second pressure, the wafer is subjected to inspection by electron beam tool 100 . In some embodiments, electron beam tool 100 may include a single beam inspection tool. In other embodiments, electron beam tool 100 may include a multi-beam inspection tool.

Controller 109 is electronically connected to electron beam tool 100 . Controller 109 may be a computer configured to perform various controls of charged particle beam detection system 1 . Controller 109 may also include processing circuitry configured to perform various signal and image processing functions. Although the controller 109 is shown in FIG. 1 as being external to the structure including the main chamber 10, the load/lock chamber 20, and the EFEM 30, it should be understood that the controller 109 may be part of the structure. While the present invention provides an example of a main chamber 10 housing an electron beam inspection tool, it should be noted that aspects of the invention are not limited to chambers housing electron beam inspection tools in its broadest sense. Indeed, it should be understood that the foregoing principles may also be applied to other tools operating under second pressure.

FIG. 2A illustrates a charged particle beam device that may be an example of an electron beam tool 100 consistent with an embodiment of the present invention. The electron beam tool 100A (also referred to herein as device 100A) may be a single beam SEM tool used in a charged particle beam detection system 1. Device 100A may include a primary beam source that includes an anode 102 and a cathode 103. A voltage may be applied between the anode 102 and the cathode 103, and a primary beam 161 may be emitted along an axis 105. Axis 105 may be a main optical axis of the SEM.

The primary beam 161 may pass through the gun aperture 122 and the beam limiting aperture 125 . Beam limiting aperture 125 may include an adjustable aperture plate. Gun aperture 122 and beam limit aperture 125 can be determined The size of the electron beam entering the condenser lens 126. A condenser lens 126 may be provided below the beam limiting aperture 125 (eg, downstream of the beam limiting aperture 125). Concentrator lens 126 may be configured to focus primary beam 161 before it enters cylindrical aperture 135 . Post aperture 135 may also include an adjustable aperture plate.

In some embodiments, the device 100A may include an additional lens 148 for manipulating the primary beam 161. For example, the lens 148 may be controlled to adjust the beam current. The lens 148 may also include another lens that may be controlled to adjust the beam spot size and beam shape. For example, such lenses of the lens 148 may be any type of lens, such as a quadrupole lens.

The beam current of the primary beam 161 can be determined by the apertures including the gun aperture 122, the beam limiting aperture 125 and the column aperture 135, and the lenses including the focusing lens 126 and the quadrupole lens 148.

As shown in FIG. 2A , the apparatus 100A may include a motorized stage 134 and a wafer holder 136 supported by the motorized stage 134 to hold a wafer 150 to be inspected. The apparatus 100A further includes an objective assembly 132, a beam splitter 158, and a detector 144. In some embodiments, the objective assembly 132 may include a modified oscillating objective delayed immersion lens (SORIL) including a pole piece 132a, a control electrode 132b, a deflector 132c, and an excitation coil 132d. The apparatus 100A may additionally include an energy dispersive x-ray spectrometer (EDS) detector (not shown) that may be used to characterize materials on the wafer.

In operation, device 100A may be used to inspect wafer 150 mounted on wafer holder 136 . Primary beam 161 may travel through the SEM column of device 100A. Deflector 132c can deflect primary beam 161 to scan across a location on the surface of wafer 150 . In the objective lens assembly 132, the excitation coil 132d and the magnetic pole piece 132a can generate a magnetic field starting at one end of the magnetic pole piece 132a and ending at the other end of the magnetic pole piece 132a. Control electrode 132b may be electrically isolated from pole piece 132a Isolated and controllable electric field that affects the beam focus. Primary beam 161 may be projected onto wafer 150 and may form beam spot 170 .

The portion of wafer 150 illuminated by primary beam 161 (eg, at beam point 170) may emit secondary particles, such as secondary electrons or backscattered electrons. Beam splitter 158 may direct secondary particles traveling back from wafer 150 to the sensor surface of detector 144 . Beam splitter 158 can change the direction of the beam. Beam splitter 158 may selectively change the direction of a beam, for example, based on the speed or energy of the beam passing through beam splitter 158 . Beam splitter 158 may be configured to redirect the secondary particle beam directed back from wafer 150 toward beam splitter 158 so that it is directed toward detector 144 where primary beam 161 passes When passing through the beam splitter 158, the trajectory of the primary beam 161 does not change. For example, beam splitter 158 may be aligned with axis 105 and may allow primary beam 161 to travel along axis 105 as the secondary particle beam is turned away from axis 105 . In some embodiments, beam splitter 158 may be configured to deflect primary beam 161 while the secondary particle beam is allowed to travel back from wafer 150 through beam splitter 158 without changing its trajectory. In some embodiments, beam splitter 158 may be configured to deflect primary beam 161 and secondary particle beams. Beam splitter 158 may include components that generate a magnetic field. Beam splitter 158 may be connected to controller 109 and may operate based on signals transmitted from controller 109 .

Detector 144 may generate signals (eg, voltage, current, etc.) representative of the intensity of received charged particles and provide these signals to a processing system such as controller 109 . As shown in Figure 2A, detector 144 may be connected to controller 109. The intensity of the secondary particle beam and the resulting beam spot on detector 144 may vary depending on the external or internal structure of wafer 150 . Additionally, as discussed above, primary beam 161 may be projected onto different portions of the top surface of wafer 150 to produce secondary particle beams (and resulting beam spots) of varying intensities. Therefore, by converting the intensity of the beam point Mapping the portions of the wafer 150 , the processing system can reconstruct an image reflecting the internal or external structure of the wafer 150 . Controller 109 may include an image processing system.

Figure 2B illustrates a charged particle beam apparatus that may be an example of electron beam tool 100 consistent with embodiments of the invention. Electron beam tool 100B (also referred to herein as device 100B) may be a multi-beam tool for use in charged particle beam detection system 1 . Device 100B may include electron source 202 . Electron source 202 may be configured to generate an electron beam along primary optical axis 201 .

As shown in Figure 2B, device 100B may include an electron source 202, a gun aperture 204, a condenser lens 206, a primary electron beam 211 emitted from the electron source 202, a source conversion unit 212, and a plurality of beamlets of the primary electron beam 211 214, 216 and 218, primary projection optical system 220, wafer stage (not shown in FIG. 2B), a plurality of secondary electron beams 236, 238 and 240, secondary optical system 242 and electronic detection device 244. Electron source 202 may generate primary particles, such as electrons of primary electron beam 211 . Controllers, image processing systems, and the like may be coupled to electronic detection device 244 . Primary projection optical system 220 may include a beam splitter 222, a deflection scanning unit 226, and an objective lens 228. Electronic detection device 244 may include detection sub-regions 246, 248, and 250.

The electron source 202, gun aperture 204, condenser lens 206, source conversion unit 212, beam splitter 222, deflection scan unit 226 and objective lens 228 may be aligned with the main optical axis 201 of the device 100B. The secondary optical system 242 and the electronic detection device 244 may be aligned with the secondary optical axis 252 of the device 100B.

Electron source 202 may include a cathode, extractor, or anode, from which primary electrons may be emitted and extracted or accelerated to form primary electron beam 211 with crossover (virtual or real) 208 . Primary electron beam 211 can be visualized as self-crossing 208 emission. The gun aperture 204 blocks peripheral electrons of the primary electron beam 211 to reduce the size of the detection spots 270, 272, and 274.

Source conversion unit 212 may include an array of image forming elements (not shown in Figure 2B) and a beam limiting aperture array (not shown in Figure 2B). Examples of source conversion unit 212 can be found in U.S. Patent No. 9,691,586; U.S. Publication No. 2017/0025243; and International Application No. PCT/EP2017/084429, which are incorporated by reference in their entirety. The array of image forming elements may include an array of micro-deflectors or micro-lenses. The image forming element array can form a plurality of parallel images (virtual or real) across 208 by a plurality of beamlets 214, 216 and 218 of the primary electron beam 211. The beam limiting aperture array can limit a plurality of beamlets 214, 216, and 218.

The focusing lens 206 can focus the primary electron beam 211. The current of the beamlets 214, 216 and 218 downstream of the source conversion unit 212 can be varied by adjusting the focusing magnification of the focusing lens 206 or by changing the radial size of the corresponding beam limiting apertures in the beam limiting aperture array. The focusing lens 206 can be an adjustable focusing lens that can be configured so that the position of its first principal surface can be moved. The adjustable focusing lens can be configured to be magnetic, which can cause the off-axis beamlets 216 and 218 to land on the beamlet limiting apertures at a rotation angle. The rotation angle varies with the focusing magnification of the adjustable focusing lens and the position of the first principal plane. In some embodiments, the adjustable focusing lens may be an adjustable anti-rotation focusing lens, which involves an anti-rotation lens having a movable first principal plane. Examples of adjustable focusing lenses are further described in U.S. Publication No. 2017/0025241, which is incorporated by reference in its entirety.

The objective lens 228 can focus the small beams 214, 216 and 218 onto the wafer 230 for detection and form a plurality of detection light spots 270, 272 and 274 on the surface of the wafer 230.

In some embodiments, condenser lens 206 may distort the wavefront of each of beamlets 214, 216, and 218. Additionally, objective 228 may be configured to focus a representation of the wavefront onto the surface of wafer 230, thereby imaging electron source 202. However, the aberration introduced by the objective lens 228 can distort the shape of the wavefront away from the ideal shape, resulting in blurred images on the surface.

Beam splitter 222 may be a means of generating electrostatic dipole fields and magnetic dipole fields. Beam splitter of Wien filter type. In some embodiments, the force exerted on the electrons of beamlets 214, 216, and 218 by the electrostatic dipole field may be equal in magnitude and opposite in direction to the force exerted on the electrons by the magnetic dipole field. Beamlets 214, 216, and 218 can thus pass directly through beam splitter 222 with zero deflection angle. However, the total dispersion of beamlets 214, 216, and 218 produced by beam splitter 222 may also be non-zero. Beam splitter 222 may separate secondary electron beams 236 , 238 , and 240 from beamlets 214 , 216 , and 218 and direct secondary electron beams 236 , 238 , and 240 toward secondary optical system 242 . Beam splitter 222 may direct the beamlet toward secondary optical system 242 by deflecting the beamlet at an angle θ relative to primary optical axis 201 .

The deflection scanning unit 226 can deflect the beamlets 214, 216 and 218 so that the detection spots 270, 272 and 274 scan the area on the surface of the wafer 230. In response to the beamlets 214, 216 and 218 being incident on the detection spots 270, 272 and 274, secondary electron beams 236, 238 and 240 can be emitted from the wafer 230. The secondary electron beams 236, 238 and 240 can include electrons with a distribution of energies, including secondary electrons and backscattered electrons. The secondary optical system 242 can focus the secondary electron beams 236, 238 and 240 onto the detection sub-areas 246, 248 and 250 of the electron detection device 244. Detection sub-regions 246, 248, and 250 may be configured to detect corresponding secondary electron beams 236, 238, and 240 and generate corresponding signals for reconstructing an image of the surface of wafer 230.

FIG. 3A illustrates an exemplary electron beam tool 100C that may be part of the charged particle detection system of FIG. 1 consistent with embodiments of the present invention. Electron beam tool 100C (also referred to herein as device 100C) includes an electron source 302, a first lens 306, a second lens 328, a beam splitter 322, a programmable charged particle mirror panel 300, and a voltage control 350. For simplicity, other commonly present components such as apertures and deflectors are not shown in Figure 3A. Sample 340 having sample surface 370 may be provided on a movable stage (not shown). Electron source 302, lens 306, and lens 328 may be aligned with the principal optical axis of device 100C.

The electron source 302 may include a cathode (not shown) and an extractor or anode (not shown), wherein during operation, the electron source 302 is configured to emit primary electrons from the cathode and extract or accelerate the primary electrons by the extractor or anode to form a primary electron beam, which is shown as a series of wavefronts, that is, multiple surfaces, surfaces, real or virtual, under which the oscillations are in phase. As can be seen, the wavefront of the beam emitted by the source 302 is shown to be substantially spherical.

The beam splitter 322, the mirror panel 300, and the voltage control 350 are introduced into the beam path to correct aberrations. The beam splitter 322, the mirror panel 300, and the voltage control 350 are introduced between the lenses to pre-shape the wavefront so that the net effect of the pre-shaping and the aberrations is a more properly focused beam. As will be understood as described in more detail below, the placement of the beam splitter 322, the mirror panel 300, and the voltage control 350 in the device 100C is merely an example, and the beam splitter 322, the mirror panel 300, and the voltage control 350 may be placed in other locations in the device 100C. The beam splitter 322 may function similarly to the beam splitter 222 in FIG. 2B and may direct the incoming beamlet toward the mirror panel 300 and further direct the reflected beam from the mirror panel 300 in another direction. The mirror panel 300 may correct the aberration of the incoming beamlet and reflect the corrected beamlet toward the beam splitter 322.

Also, in the examples described below, the mirror panel 300 is mainly described in terms of correcting aberrations generated by lenses. However, the mirror panel 300 may also or alternatively be used to shape the charged particle beam. For example, the mirror panel 300 can be used to make the beam cross-sectional profile on the sample a ring rather than a point. In certain applications, this may provide advantages, such as for imaging the sidewalls of contact holes. As another example, the beam profile can be made less divergent at the wafer to produce a greater depth of focus.

In some embodiments, device 100C may include additional optical elements (such as electrodes) paired with adjustable voltage or magnetic optical elements paired with adjustable excitation. The components are placed between the mirror panel 300 and the separator 322 to further influence the electric and magnetic fields to correct aberrations. A plurality of drivers may be coupled with an electrode or a magnetic optical element, wherein each of the plurality of drivers may be configured to provide an adjustable voltage or an adjustable excitation to a corresponding electrode or corresponding magnetic optical element, respectively. Additional optical elements coupled to mirror panel 300 may be used to correct for possible additional aberrations caused by lens 306 or beam splitter 322, such as those caused by multipole fields. For example, in one example implementation, the mirror panel 300 can be used to correct rotationally symmetric aberrations or asymmetric aberrations, and additional optical elements can be used to correct asymmetric aberrations caused by multipolar fields.

The mirror panel 300 can reflect the beamlets above the mirror surface by applying a negative or positive total voltage to the mirror panel 300. For example, the voltage control 350 can apply a negative total voltage to the mirror panel 300 to reflect electrons (or negative ions) from the beamlets. In another example, the voltage control 350 can apply a positive total voltage to the mirror panel 300 to reflect positively charged particles (or positive ions) from the beamlets. The beamlets are reflected toward the beam splitter 322, where the reflected beamlets are directed in another direction and can be focused on the sample. FIG. 3A shows the beamlets bent at 90 degrees, and it should be understood that the beamlets can be bent at other angles. Additionally, the mirror panel 300 may be further configured to reflect only one of the multiple beamlets.

In some embodiments, mirror panel 300 and voltage control 350 may be implemented in separate components. In some other embodiments, mirror panel 300 and voltage control 350 may be implemented in a single component.

In some implementations, a second mirror panel may be provided to reflect beamlets that have been reflected by mirror panel 300 inside device 100C. For example, beamlets reflected from mirror panel 300 may be directed to a second mirror panel implemented within device 100C (such as near beam splitter 322). The second mirror panel can reflect the incident beamlet from the beam splitter 322 toward the second beam splitter, where the second beam splitter directs the reflected beamlet in another direction and can focus on the sample. superior.

Referring now to FIG. 3B , a schematic diagram illustrating the operation of a programmable pixelated mirror panel 300 and a voltage control 350 consistent with some embodiments of the present invention is shown. The mirror panel 300 may include a set of pixels 301 to 307 for shaping the profile of a beamlet proximate to the set of pixels. The voltage control 350 may include a set of control components 351 to 357 associated with each of the set of pixels 301 to 307, respectively. Each pixel control component 351 to 357 is configured and arranged to apply a signal (e.g., a voltage) to the associated pixel. The mirror panel 300 is thus programmable in that voltages may be provided differently to each pixel or group of pixels and may be varied as desired. The voltage provided by each of the pixel control components 351 to 357 can generate a curved isopotential plane (custom electric field) 390 above the mirror plate 300. The isopotential plane 390 can determine where the electrons from different parts of the beamlet 361 are reflected, and the reflection affects the shape and phase of the beamlet 361r reflected by the mirror plate 300. Therefore, the adjustment of the voltage controls the aberration by locally adjusting the beamlet 361 (that is, one or more locations of the beamlet 361 affected by the isopotential plane 390), and enables the reflected beamlet 361r to obtain one or more desired characteristics, such as focusing at a point on the sample with a desired resolution. Although the mirror panel 300 is configured to have seven pixels and corresponding seven control elements, it should be understood that different numbers of pixels and control elements may be configured, and the pixels or control elements may be configured in any of a variety of configurations.

In some embodiments, pixels 301 to 307 and corresponding pixel control components 351 to 357 may each be implemented in a separate component. In other embodiments, pixels 301 to 307 and corresponding pixel control components 351 to 357 may be implemented in a single component.

Pixels 301 to 307 may each include a rectangular shape. It should be apparent that the pixels may comprise other shapes, such as hexagons, ring segments, squares, another suitable shape, or a combination of these shapes. For example, beamlets are often rotationally symmetric and therefore used as ring segments Shared pixels provide the advantage of reducing the voltage control required and the number of pixels. As another example, by using hexagonal pixels instead of square pixels, more pixels can be implemented in the same area.

In some embodiments, the size of the pixels or the shape of the pixels 301 - 307 may vary throughout the mirror panel 300 . For example, smaller pixels may be used in areas of mirror panel 300 that require more precise correction, and may therefore provide greater accuracy in correcting aberrations. Voltage control 350 can provide voltage to each of these corresponding smaller pixels to provide a more accurate beam shape. In some embodiments, each of pixels 301-307 may be uniquely controlled. For example, voltage control may provide, for example, a negative voltage to some pixels to reflect negatively charged particles that interact with those pixels, and a positive voltage may be provided to other pixels to attract particles that may fall within the pixels preferred for that pixel. Charged particles outside the shaping beam.

In some implementations, the mirror panel 300 may include larger pixels to make beam shaping easier to control and implement. For example, larger pixels may each cover a larger area than smaller pixels and may provide similar effects on incident beamlets (e.g., such as reflection or attraction). In some implementations, the mirror panel 300 may include larger and smaller pixels, where larger pixels may be used in portions of the mirror panel where beamlets are expected to be uniformly reflected, and smaller pixels may be used on the periphery where beamlets are expected to interact, so as to provide more control over beam shape.

In some embodiments, mirror panel 300 is bendable. When the mirror panel 300 is bent, the voltage used to correct aberrations can be reduced. Mirror curvature can be mechanically adjusted and controlled by mechanical actuators such as piezoelectric motors.

In some embodiments, individual pixels implemented in the mirror panel 300 can be tilted by using individual pixels with a mechanically tiltable upper surface. The tiltable pixels can be mechanically adjusted and controlled by mechanical actuators such as piezoelectric motors. The tilted pixels can remove charged particles from the incident beamlet and the removed charged particles can be scattered between the mirror panel 300 and the beam splitter. The tilted pixels can produce different paths for the charged particles, which can be used to filter the charged particles from the incident beamlet using a beam aperture between the mirror panel 300 and the beam splitter or elsewhere in the charged particle beam system.

During use, a focused electron beam is scanned across the surface of the sample. During scanning of a focused electron beam across a large field of view, the shape and intensity distribution (eg, spot profile) of the source's image on the surface of the sample can change. The use of programmable mirror panel 300 provides the ability to correct or reduce these scanning effects by dynamically configuring programmable mirror panel 300. As explained above, programmable mirror panel 300 can be configured as a panel having pixels 301-307 and individual voltage controls 351-357 for each pixel. The phase of the electron wave can be locally changed by adjusting the voltage at the pixel using voltage control 350, which can provide an AC voltage to the pixel to produce a time-dependent beam shape by non-deterministic reflection of the incident beamlet. For example, the portion of the electron wave reflected above the pixel may enable or facilitate control of the formation of an electron spot (probe). As a specific example, synchronizing the mirror panel voltage with the scanning of the electron beam across the sample enables or facilitates dynamic control of probe formation throughout the scanned field of view. In another example, when scanning a large field of view over a sample, more aberrations may occur in the outer edges of the beamlet compared to the center. By applying an AC voltage to the mirror panel 300, aberrations in the outer edges of the beamlet can be corrected more accurately.

In some embodiments, the mirror panel 300 may provide for using different pixel voltage distributions in different directions across the surface of the mirror panel 300. The beam splitter 322 may add aberrations to the beamlets and these aberrations may be rotationally asymmetric because the beamlets are deflected in one direction. Therefore, the beamlets lose the rotationally symmetric beam shape and to correct the shape, the mirror panel may use different pixel voltage distributions in two different directions.

Referring now to FIG. 3C , another diagram illustrating the operation of a programmable pixelated mirror panel 400 and voltage control 450 for correcting different aberrations of different beamlets in a multi-beam system, consistent with some embodiments of the present invention. A schematic diagram. The mirror panel 400 may include three groups of pixels 401 to 405, 411 to 415, and 421 to 425, and the voltage control 450 may include three groups of control members 451 to 455, 461 to 465 and 471 to 475. Each pixel control member 451-455, 461-465, and 471-475 is configured and configured to apply a signal (eg, a voltage) to the associated pixel. The voltage provided by each of the pixel control members 451 to 455, 461 to 465, and 471 to 475 can generate corresponding three curved equipotential planes 491 to 493 (customized electric fields) above the mirror panel 400. The equipotential planes determine where electrons from different portions of the three beamlets are reflected, and this reflection affects the shape and phase of each of the beamlets reflected by mirror panel 400.

Each group of pixels implemented in the mirror panel 400 can further reflect the beamlets at different heights above the surface of the mirror panel 400 by providing different voltages to each group of pixels. Accordingly, the mirror panel 400 can affect the shape and phase of each of the plurality of beamlets and reflect the affected beamlets at different angles toward the beam splitter, thereby enabling the SEM to obtain one or more desired characteristics, such as Each of the beamlets is focused at a different point on the sample at the desired resolution. Furthermore, in addition to or instead of controlling the phase, the mirror panel 400 can also locally control the amplitude of the electron wave by locally removing charged particles from portions of the incident beamlet. The mirror panel 400 can control the amplitude by preventing the charged particles in the beamlets from reflecting toward the beam splitter, for example by attracting the charged particles to the pixels rather than reflecting the charged particles.

In some embodiments, the mirror panel 400 can locally remove electrons from the beamlet by using positive voltages on the pixels. Positively charged pixels can attract electrons above the pixel toward the mirror panel 400 and absorb or scatter electrons on the surface of the mirror panel 400 .

Mirror panel 400 can also remove positively charged particles in the beamlet by using negative voltages on the pixels. Scattered particles or secondary electrons originating from the mirror panel 400 can have different paths between the mirror panel 400 and the beam splitter by placing the beam aperture between the mirror panel 400 and the beam splitter. or filtered out from a suitable location elsewhere in the charged particle beam system.

The voltage distribution across the pixels may be different for each set of pixels assigned to a particular beamlet or for each mirror panel. In some embodiments, the voltage distribution may be the same for certain sets of pixels or mirror panels to limit the number of individual voltage controls required.

The voltage distribution across the pixels and the total mirror panel voltage can be adjusted based on the landing energy of the beamlets, allowing correction or reduction of aberrations under different electron beam system settings associated with different landing energies. The voltage distribution across the pixel can be adjusted based on the position of the beamlet on the sample. For example, the position of the beamlet can be a measure of whether or how far the beamlet is off-axis from the desired beam point, in order to optimize the respective distances of the beamlet. Correction or reduction of aberrations at axial positions.

The voltage distribution across the pixels and the total mirror panel voltage can be adjusted based on the beamlet current, allowing correction or reduction of aberrations under different electron beam system settings associated with different beamlet currents. The voltage distribution across the pixels and the total mirror panel voltage can be adjusted based on the beamlet's landing angle at the sample, allowing correction or reduction of aberrations under different electron beam system settings associated with different landing angles.

The voltage distribution across the pixels and the total mirror panel voltage can be adjusted based on the electric field at the sample, allowing correction or reduction of aberrations under different electron beam system settings associated with different electric fields at the sample.

Although the mirror panel 400 of FIG. 3C is configured to have three sets of pixels and associated three control elements to correct the aberrations of the three beamlets, it should be understood that different numbers of sets of pixels, control elements, and beamlets may be configured in any of a variety of configurations.

Referring now to FIG. 4 , which is a flow chart illustrating an exemplary method 500 for correcting aberrations of a beamlet consistent with an embodiment of the present invention. The method 500 may be performed by an electron beam tool (e.g., the electron beam tool 100C of FIG. 3A ). Furthermore, although the method 500 describes correcting aberrations of a single beamlet, it should be understood that the method 500 may also be applied to correct aberrations of a plurality of beamlets.

In step 510, the beamlets are directed toward a programmable charged particle mirror panel (e.g., programmable charged particle mirror panel 300 of FIG. 3A). For example, the beamlets may be directed by a beam splitter (e.g., beam splitter 322 of FIG. 3A). In some embodiments, a controller (e.g., controller 109 of FIG. 1) may instruct the beam splitter to direct the beamlets toward the programmable charged particle mirror panel.

In step 520, a signal (eg, voltage) is provided to the pixels of the programmable charged particle mirror panel (eg, pixels 301 to 307 of FIG. 3B). In some embodiments, these signals may be provided by voltage controls (eg, voltage control 350 of FIG. 3A), where each pixel may have a corresponding voltage control (eg, voltage controls 351 to 357 of FIG. 3B). In some embodiments, the signal provided may be a negative voltage to reflect electrons (or negative ions) and attract positively charged particles from the beamlet. In some embodiments, the signal provided may be a positive voltage to reflect positively charged particles (or positive ions) and attract electrons from the beamlet.

The pixel may include a group of pixels for influencing the guided beamlet. For example, the group of pixels may be configured to shape the profile of a beamlet proximate to the group of pixels. Each of the group of pixels in the mirror panel may have an individual voltage control configured to establish a voltage in the pixel. The mirror panel is thus programmable because voltages may be provided differently to each pixel or set of pixels and may be varied as desired. The provided voltages may generate custom electric fields (e.g., equipotential planes 390 of FIG. 3B ) determined to shape the profile of the beamlet. Adjustment of the voltage may also change the phase of the electrons contained in the beamlet.

In step 530, the shaped beamlets are reflected by the programmable charged particle mirror panel to reduce aberrations. The small beams are reflected above the surface of the mirror panel by a voltage applied to the pixels on the mirror panel.

In some embodiments, method 500 may further include an additional step of directing the shaped beamlet to a sample surface (e.g., sample surface 370 of FIG. 3A ). Before reaching the sample surface, the shaped beamlet may be further affected by an objective lens (e.g., second lens 328 of FIG. 3A ) that may be used to focus the shaped beamlet onto the sample surface.

Embodiments may be further described using the following terms:

1. A device comprising: a first set of pixels configured to shape a first beamlet proximate to the first set of pixels; and a first set of pixel control components respectively associated with each of the first set of pixels, each pixel control component being configured and arranged to apply a signal to the associated pixel for shaping the first beamlet.

2. The device of clause 1, wherein the first set of pixels has a voltage distribution configured to adjust based on a reflection of charged particles associated with the first beamlet above the first set of pixels.

3. A device as claimed in any one of clauses 1 or 2, wherein the first beamlet is shaped to induce a reduction of an aberration.

4. A device as claimed in any one of clauses 1 to 3, wherein the first set of pixels and the first set of pixel control components are implemented in a component.

5. A device as claimed in any one of clauses 1 to 3, wherein the first set of pixels and the first set of pixel control components are implemented in separate components.

6. A device as claimed in any one of clauses 1 to 3, wherein each pixel in the first set of pixels and a corresponding pixel control component in the first set of pixel control components are implemented in a component.

7. The device of any one of clauses 1 to 3, wherein each pixel in the first set of pixels and a corresponding pixel control component in the first set of pixel control components are implemented in a separate component.

8. The device of any one of clauses 1 to 7, wherein the signal triggers the associated pixel to generate an electric field for shaping the first beamlet.

9. A device as claimed in any one of clauses 1 to 7, wherein the first set of pixels is further configured to reflect the shaped first beamlet.

10. A device as claimed in any one of clauses 1 to 9, wherein the signal comprises a negative voltage to enable the associated pixel to reflect negatively charged particles of the first beamlet or to remove positively charged particles from the first beamlet.

11. The device of any one of clauses 1 to 10, wherein the first set of pixels includes a subset of pixels tilted to remove charged particles from the first beamlet.

12. A device as claimed in any one of clauses 1 to 9, wherein the signal comprises a positive voltage to enable the associated pixel to reflect positively charged particles of the first beamlet or to remove negatively charged particles from the first beamlet.

13. The apparatus of any one of clauses 1 to 12, wherein the signal includes an AC voltage to shape the profile of the first beamlet in synchronization with scanning of the beam across a sample.

14. The device of any one of clauses 1 to 13, further comprising: a second set of pixels configured to shape a second beamlet proximate to the second set of pixels; and a second set of pixel control components respectively associated with each of the second set of pixels, each pixel control component being configured and arranged to apply a signal to the associated pixel for shaping the second beamlet.

15. The device of clause 14, wherein the first set of pixels and the second set of pixels are part of a mirror panel.

16. The device of clause 14, wherein each of the first set of pixels and the second set of pixels comprises a set of rectangular, hexagonal or ring-shaped segment pixels.

17. A device as claimed in any one of clauses 14 to 16, wherein the first set of pixels and the second set of pixels are arranged in a square or hexagonal pattern.

18. A device as claimed in clause 1, wherein the first set of pixels comprises pixels of different sizes and shapes.

19. A device as in clause 1, wherein the first set of pixels is disposed on a plate-shaped member, and the plate-shaped member is curved, and the curvature of the plate-shaped member is adjusted by a mechanical actuator.

20. A device as claimed in clause 1, wherein the first set of pixel control components is configured to apply a negative voltage, zero or a positive voltage to shape the first beamlet.

21. The device of clause 1, wherein the first set of pixels has a voltage distribution configured to adjust based on a landing energy of charged particles associated with the first beamlet.

22. The device of clause 1, wherein the first set of pixels has a voltage distribution configured to adjust based on a current of charged particles associated with the first beamlet.

23. The device of clause 1, wherein the first set of pixels has a voltage distribution configured to adjust based on a landing angle at a sample.

24. The device of clause 1, wherein the first set of pixels has a A voltage distribution adjusted by a magnitude of an electric field.

25. A system for manipulating a charged particle beamlet, comprising: a source of a beamlet of charged particles; and a programmable charged particle mirror panel configured to receive the beamlet and configured to shape the beamlet.

26. The system of clause 25, further comprising: a plurality of electrodes configured to affect the guided beamlet; and a plurality of drivers respectively associated with each of the plurality of electrodes, each driver configured to provide an adjustable voltage.

27. The system of clause 25, further comprising: a plurality of electromagnetic optical elements coupled to the adjustable excitation element and configured to affect the guide beamlet; a plurality of drivers respectively connected to the plurality of Each of the electromagnetic optical elements is associated, and each driver is configured to adjust the excitation of the corresponding electromagnetic optical element.

28. The system of clause 25, further comprising: a beam splitter configured to direct the beamlet to the programmable charged particle mirror panel, wherein the programmable charged particle mirror panel can be further configured to direct the shaped beamlet to the beam splitter.

29. The system of clause 28, wherein the beam splitter is configured to receive and direct a plurality of beamlets, and the programmable charged particle mirror panel is configured to receive and reflect the plurality of beamlets .

30. The system of clause 25, wherein the programmable charged particle mirror panel has a plurality of controlled pixels in the mirror panel, each of the plurality of beamlets corresponding to an associated set of controlled pixels configured to shape the corresponding beamlet.

31. A method for shaping a beamlet of charged particles, the method comprising: using a beam splitter to direct a first beamlet of charged particles toward a charged particle mirror panel; and using the charged particle mirror panel The particle mirror panel shapes the first beamlet and reflects the shaped beamlet by providing a signal to a first group of pixels of the charged particle mirror panel to generate an electric field.

32. The method of clause 31, wherein the shaped beamlet is directed to the beam splitter.

33. The method of clause 31, further comprising: directing a second beamlet of charged particles toward the charged particle mirror panel using the beam splitter; and shaping the second beamlet using the charged particle mirror panel by providing a signal to a second set of pixels of the charged particle mirror panel to generate an electric field and reflecting the shaped beamlet to the beam splitter.

34. A non-transitory computer-readable medium storing a set of instructions executable by a controller of a device to cause the device to perform a method for shaping a beamlet of charged particles, the method Comprising: using a beam splitter to direct a first beamlet of charged particles toward a charged particle mirror panel; and using the charged particle mirror panel by providing a signal to a first set of the charged particle mirror panel The pixels generate an electric field to shape the first beamlet and reflect the shaped beamlet to the beam splitter.

35. The non-transitory computer-readable medium of clause 34, wherein the set of instructions is executable by the controller of the device to cause the device to further perform the following operations: directing a second beamlet of charged particles toward the charged particle mirror panel using the beam splitter; and shaping the second beamlet by providing a signal to a second set of pixels of the charged particle mirror panel to generate an electric field and reflecting the shaped beamlet from the charged particle mirror panel to the beam splitter.

In some embodiments, a controller may control a charged particle beam system. The controller may include a computer processor. The controller may instruct components of the charged particle beam system to perform various functions, such as controlling various drivers for manipulating one or more beamlets, for controlling a beam splitter for directing the beamlets, and for controlling voltage control and corresponding pixels of a programmable charged particle mirror panel. The controller may include storage as a storage medium, such as a hard drive, cloud storage, random access memory (RAM), other types of computer readable memory, and the like. The controller may communicate with the cloud storage. A non-transitory computer-readable medium may be provided that stores instructions for causing the processor of controller 109 to perform beamforming or other functions and methods consistent with the present invention. Common forms of non-transitory media include, for example: floppy disks, flexible disks, hard disks, solid-state drives, magnetic tapes, or any other magnetic data storage media; CD-ROMs; any other optical data storage media; any physical media with a hole pattern; RAM, PROM and EPROM, FLASH-EPROM or any other flash memory; NVRAM; cache memory; registers; any other memory chip or cartridge; and networked versions thereof.

As used herein, unless specifically stated otherwise, the term "or" encompasses all possible combinations unless not feasible. For example, if the statement component can include A or B, then Unless otherwise specifically stated or impracticable, components may include A, or B, or A and B. As a second example, if it is stated that a component may include A, B, or C, then unless otherwise specifically stated or impracticable, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

Although various embodiments have been combined to describe embodiments of the present invention, it should be understood that various modifications and changes may be made without departing from the scope of the present invention. It is intended that this specification and examples be considered illustrative only.

100C: Electron beam tools/devices

300: Programmable charged particle mirror panel

302:Electron source

306:First lens

322: Beam splitter

328: Second lens

340: Sample

350:Voltage control

370: Sample surface

Claims (15)

A device for controlling a charged particle beam, comprising: a first set of pixels configured to shape a first beamlet proximate to the first set of pixels; and a first set of pixel control components respectively associated with each of the first set of pixels, each pixel control component being configured and configured to apply a signal to the associated pixel for shaping the first beamlet, wherein each pixel control component is configured to generate a curved equipotential plane above the associated pixel so that the shaping of the first beamlet is affected to obtain a desired characteristic. The device of claim 1, wherein the first set of pixels has a voltage distribution configured to adjust based on a reflection of charged particles associated with the first beamlet above the first set of pixels. A device as claimed in claim 1, wherein the first beamlet is shaped to cause a reduction in an aberration. The device of claim 1, wherein the first set of pixels and the first set of pixel control components are implemented in a component. A device as claimed in claim 1, wherein the first set of pixels and the first set of pixel control components are implemented in separate components. The device of claim 1, wherein each pixel in the first set of pixels and a corresponding pixel control component in the first set of pixel control components are implemented in a component. A device as claimed in claim 1, wherein each pixel in the first set of pixels and a corresponding pixel control component in the first set of pixel control components are implemented in a separate component. The device of claim 1, wherein the signal triggers the associated pixel to generate an electric field for shaping the first beamlet. The device of claim 1, wherein the first set of pixels is further configured to reflect the shaped first beamlet. The device of claim 1, wherein the signal includes a negative voltage to enable the associated pixel to reflect negatively charged particles of the first beamlet or to remove positively charged particles from the first beamlet. The device of claim 1, wherein the first set of pixels includes a subset of pixels tilted to remove charged particles from the first beamlet. The device of claim 1, wherein the signal includes a positive voltage to enable the associated pixel to reflect the positively charged particles of the first beamlet or to remove negatively charged particles from the first beamlet. The device of claim 1, wherein the signal comprises an AC voltage to synchronously shape the profile of the first beamlet as the beam is scanned across a sample. The device of claim 1, further comprising: a second set of pixels configured to shape a second beamlet proximal to the second set of pixels; and a second set of pixel control members respectively and Associated with each of the second set of pixels, each pixel control member is configured and configured to apply a signal to the associated pixel for shaping the second beamlet. A method for shaping a beamlet of charged particles, the method comprising: using a beam splitter to direct a first beamlet of charged particles toward a charged particle mirror panel; and using the charged particle mirror The panel shapes the first beamlet by providing a signal to a first group of pixels of the charged particle mirror panel to create a curved equipotential plane above the associated pixel and reflect the shaped first beamlet , wherein the shaping of the first beamlet is influenced to obtain a desired characteristic.